Method of making aluminium hydrate.



- 30 cent. of the whole.

.UNITE HARRY IV. JORDAN, OF SYRACUSE, NEW YORK, ASSIGNOR TO THE PITTS- BURGH REDUCTION COMPANY, OF PITTSBURG, PENNSYLVANIA,

PORATI ON OF PENNSYLVANIA.

A COR- METHOD OF MAKING ALUMINIUM HYDRATE.

SPECIFICATION forming part of Letters Patent No. 691 ,4'70, dated January 21, 1902.

Application filed July 10, 1901. $eria1 No. 67,792. (No specimens.) A

To aZZ whom it nuty concern.-

Be it known that I, HARRY W. JORDAN, of Syracuse, Onondaga county, New York, have invented a new and useful Improvement in 5 the Manufacture of Aluminium Hydrate, of which the followingis afull, clear, and exact description.

My invention relates to an improvement in the manufacture of aluminium hydrate by a to process wherein the hydrate is precipitated from sodium-aluminate solution by carbonicacid gas. In such processes aluminium hydrate is precipitated from the aluminate liquor according to the following formula;

The precipitation of the hydrate is carried on in a vessel known as an agitator, consisting of ahorizontal cylinder fitted with rotating paddles and having an inlet and outlet pipe for the passage of CO gas. I-Ieretofore the precipitation has been carried on generally at from 160 Fahrenheit to 170 2 5 Fahrenheit, and even with the exercise of great care it has been found that there is precipitated with the aluminium hydrate an insoluble sodium compound which varies in amount from three per cent. to seven per It can be removed in part by washing with dilute sulfuric acid; but this adds to the expense and contaminates the aluminium hydrate with objectionable sulfate. I have discovered that if the ()0 gas be superheated above 200 Fahren- 'heit,above the normal boiling-point of the solution, and preferably to a temperature of 400 Fahrenheit before being introduced into the agitator, greatly-im proved results are obtained, the proportion of insoluble sodium carbonate is greatly reduced, and the washing with acid rendered unnecessary. With CO gas heated to about 280 Fahrenheit I have obtained aluminium hydrate having an average of about 1.32 per cent. of insoluble sodium carbonate, and with CO gas heated to about 400 Fahrenheit I have obtained an average of only about .43 per cent. of insoluble sodium carbonate.

The means by which my invention is put in practice may be varied, since What I claim is 1. The method herein described of making aluminium hydrate, which consists in preheating 00 gas to a temperature above 200 Fahrenheit and bringing it into contact with the aluminate solution, substantially as described.

2. The method herein described of making I HARRY W. JORDAN.

Witnesses:

MORRIS W. CHASE, ALBERT O. PHILLIPS. 

